Soon to be C owner (maybe) Questions about proper pricing

Hey all! I've been researching and lurking for some time now, and I am very very close to making my first Prius purchase! I'm quite nervous since this will be my first time buying a car, so I have questions.

1. I'm really in it for the fuel efficiency and longevity the Prius seems to bring to the table. My only concern is that I will be using this car for long distance trips maybe 3 times a year for out of state conventions. The rest of the time will just be within my city. I understand that you get the best mpg during coasting and braking, so I'm concerned that I might be barking up the wrong tree when it comes to fuel efficiency and my choice of car. Should I be looking into something completely different? How does your Prius handle long trips?
2. I've read lots of posts about the oil burning issues with the 2010-2014 models. Is it as bad as it seems? I have been avoiding models from these years and older because I don't have the extra money to shell out for repairs so soon after purchase. Most if not all models under 2016 are still coming up $8-$13k so I'm having a really hard time figuring out what to do when my budget is $10k sticker price.
3. I might have jumped the gun on this one, but I can still back out as I have yet to sign official paperwork and hand over money to the dealership. I came across a 2016 pc with a little over 106k miles on the odometer (holy crap yeah I know) for $9.9k. I checked the Carfax and it was in what seems to be a minor accident, only sustaining front right bumper damage. Where I came to see it last week it was still being worked on, but was able to test drive it yesterday. It looks great, besides the pounds of dog hair in the interior, and it runs so smooth and quiet, although I really have no other Prius to go off of. Now after everything I'm looking at 11k out the door after a $500 trade in. This is coming from an actual Toyota dealership, so I at least have that piece of mind. My concern is that I'm getting completely shafted and should run away from the deal immediately. I'm really new to the hybrid world and don't have much to go off of. I just know I really need a car like yesterday and I really enjoyed the Prius c. Also the color is gorgeous

I'm in panic mode right now because I'm supposed to put down the money and pick up the car in 4 1/2 hours. Reading other comments and articles after we left, and I was so sure everything was fine, has left me worried. Help are gal out?

Sorry if formatting is off.